This invention concerns a method for producing a furniture element and an element which is produced by such a method.
A method of this kind is previously known from WO 96/02168 (Dranger). This method is well suited for producing elements having similar extensions in at least two dimensions. Production of more plate-like elements, such as for example elements formed as a cushion or a mattress, however, result in an unwanted convexity of the largest side walls. This result in practice in that mattresses, cushions etc. and support bodies which are extended in two dimensions have to be made from several elements which are placed inside a cover.
It is an aim of this invention to provide a blow-moulding process and elements produced in said process which eliminate this problem.
By such adhering or welding together of wall portions, a desired configuration of the walls of the element is achieved. The desired configuration is generally mainly even or repeatedly vaulted in accordance with a conventional upholstered mattress, cushion or the like. Also other configurations such as controlled curve-formed are however possible.
A main purpose of the invention is rational production in one single blow-moulding process of fillings or support bodies for pieces of furniture, beds, mattresses or elements such as cushions or pillows from a soft flexible thermoplastic material having a wall thickness of between about 0.5-1.5 mm. The dimensions in one plane of the elements is usually from about 2 mxc3x972 m and smaller and the expanded resulting elements have thicknesses between about 5 cm and 25 cm.
The resulting construction having meeting portions forming wells or ditches from at least one side also prevents pressure on one part of the element from displacing air which expands the element in another part. The support structure therefore is experienced as stable also with changed load. A further advantage associated thereto is that also the largest body weight will have sufficient support of air so as to avoid xe2x80x9cbottom touchxe2x80x9d.
It may be mentioned that in normal use the resulting element is intended to be provided with a cover which protects against wear, giving increased working life, and also a ventilated air layer between the user and the element, so as to increase comfort.
Adhering or welding together of portions of the blow-moulded work-piece will be obtained by using pressuring means, whereby the use of rod-shaped means result in portions being more or less spot-wise welded together, whereby the portions may be distributed in a pattern over a larger surface of the element.
Larger parts of the resulting expandable element may be controlled with respect to their shape by the pressuring means having plate-shape, whereby for example pivot portions between parts of the elements are easily achieved.
By the method being carried out in a modular form it is easily achieved that a large number of form sizes may be obtained at a reduced price from a small number of form components.
The invention also concerns an element which is produced in a method, said element being intended to be used as a support structure of a piece of furniture or a part of a piece of furniture such as a mattress, a cushion or the like.